This invention pertains to the field of smoking materials. More particularly, the present invention concerns a method for preparing a smoking material containing tobacco stem and/or stalk materials having reduced tar, nicotine and puff count while having no undesirable "woody taste".
As a result of the stripping of leaf tobacco in preparation for its use for cigar wrappers or filler, cigarettes and smoking tobacco, tobacco by-products, such as, stems, stalks and leaf scraps are collected. These by-products have not been very useful for direct incorporation in smoking products, although some have been used for making snuff and for mixture with chewing tobacco. Tobacco dust and the like have also been recovered resulting from shipping and handling of tobacco. Although attempts have been made in the past to economically utilize these tobacco by-products by forming "reconstituted" tobacco therefrom (see, for example, U.S. Pat. Nos. 3,409,026 and 3,386,449), such reconstituted tobacco has frequently been found to be undesirable due to the harshness, poor aromatic qualities and off-taste of the smoke produced by this material even when it is combined with natural leaf tobacco and used in very small quantities. This is particularly true where attempts have been made to utilize Burley tobacco by-products.
Moreover, even though reconstituted tobacco is made from tobacco by-products, it nevertheless possesses some of the same characteristics as natural leaf tobacco. Accordingly, it would be highly desirable to develop a method by which the less desirable constituents of a reconstituted tobacco are reduced while the flavor and aromatic properties are improved.
The reduction of tar and nicotine in tobacco leaf material has been attempted by incorporating a carbohydrate or cellulosic material which has been thermally degraded or "pyrolyzed" in an inert atmosphere into the tobacco. Such techniques are disclosed, for example, in U.S. Pat. Nos. 3,861,401, 3,861,402 and 4,019,521. Another technique described in U.S. Pat. No. 3,805,803 discloses a method by which the tar and nicotine content of a reconstituted tobacco smoking material is reduced by the incorporation of activated carbon.
The above techniques suffer from many disadvantages. In particular, they generally all require the addition of materials which are foreign to tobacco. These foreign materials may detract from and adversely affect the acceptability of the smoking product which contains such additives.